tcm_qla2xxx Add SCSI command jammer/discard capability
This patch introduces support for TCM_QLA2XXX_DEBUG and
associated tcm_qla2xxx_tpg->tpg_attrib.jam_host checking
used to test dropped packets to FC host environments.
Tested by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Laurence Oberman <loberman@redhat.com>
Acked-by: Himanshu Madhani <himanshu.madhani@qlogic.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/Documentation/scsi/tcm_qla2xxx.txt b/Documentation/scsi/tcm_qla2xxx.txt
new file mode 100644
index 0000000..c3a670a
--- /dev/null
+++ b/Documentation/scsi/tcm_qla2xxx.txt
@@ -0,0 +1,22 @@
+tcm_qla2xxx jam_host attribute
+------------------------------
+There is now a new module endpoint atribute called jam_host
+attribute: jam_host: boolean=0/1
+This attribute and accompanying code is only included if the
+Kconfig parameter TCM_QLA2XXX_DEBUG is set to Y
+By default this jammer code and functionality is disabled
+
+Use this attribute to control the discarding of SCSI commands to a
+selected host.
+This may be useful for testing error handling and simulating slow drain
+and other fabric issues.
+
+Setting a boolean of 1 for the jam_host attribute for a particular host
+ will discard the commands for that host.
+Reset back to 0 to stop the jamming.
+
+Enable host 4 to be jammed
+echo 1 > /sys/kernel/config/target/qla2xxx/21:00:00:24:ff:27:8f:ae/tpgt_1/attrib/jam_host
+
+Disable jamming on host 4
+echo 0 > /sys/kernel/config/target/qla2xxx/21:00:00:24:ff:27:8f:ae/tpgt_1/attrib/jam_host